Yeast extract and method of producng the same

Abstract

A method for producing yeast extract including 4-30% disodium inosinate and disodium guanylate (I+G), comprising a) providing a yeast cream including 8 wt. % or more of RNA, b) inactivating the yeast in the yeast cream, c) centrifugating the yeast cream and collecting a supernatant, d) degrading the supernatant with enzymes, e) heat-treating, and f) concentrating and drying the supernatant. The resultant yeast extract is natural, involves no additive, and has better flavor. The invention further provides yeast extract is produced by the method.

1 . A method for producing yeast extract comprising disodium inosinate and disodium guanylate, the method comprising the steps of:
 a) preparing a yeast cream from yeast comprising 8 wt. % or more of RNA, said yeast being a bread yeast, a fermented beer yeast, a torula, or a mixture thereof;   b) inactivating said yeast in said yeast cream under a temperature of between 40 and 95° C.;   c) centrifugating said yeast cream and collecting a supernatant;   d) adding a protease, a nuclease, and a transaminase to said supernatant and allowing to react for 12-25 hrs at 35-80° C. with a pH value of 4.0-6.8;   e) treating said supernatant at a temperature of 75-90° C. for 50-70 min so as to inactivate the enzymes; and   f) concentrating said supernatant to comprise 35-40 wt. % of a dry matter and spray drying said dry matter to yield yeast extract comprising 4-30 wt. % of disodium inosinate and disodium guanylate.   
     
     
         2 . The method of  claim 1 , wherein the temperature in step d is between 45 and 68° C. 
     
     
         3 . The method of  claim 2 , wherein a weight ratio of said protease to said nuclease to said transaminase is 1:1:1. 
     
     
         4 . The method of  claim 2 , wherein the total addition amount of said protease, said nuclease, and said transaminase is 0.1-0.3 wt. % of said dry matter in said supernatant. 
     
     
         5 . The method of  claim 1 , wherein a weight ratio of said protease to said nuclease to said transaminase is 1:1:1. 
     
     
         6 . The method of  claim 1 , wherein the total addition amount of said protease, said nuclease, and said transaminase is 0.1-0.3 wt. % of said dry matter in said supernatant. 
     
     
         7 . The method of  claim 1 , wherein the pH value in step d is between 4.5 and 6.8. 
     
     
         8 . The method of  claim 1 , wherein the reaction time in step d is between 16 and 20 hrs. 
     
     
         9 . Yeast extract comprising disodium inosinate and disodium guanylate produced by the method of  claim 1 . 
     
     
         10 . The yeast extract of  claim 9 , wherein the temperature in step d is between 45 and 68° C. 
     
     
         11 . The yeast extract of  claim 9 , wherein a weight ratio of said protease to said nuclease to said transaminase is 1:1:1. 
     
     
         12 . The yeast extract of  claim 9 , wherein the total addition amount of said protease, said nuclease, and said transaminase is 0.1-0.3 wt. % of said dry matter in said supernatant. 
     
     
         13 . The yeast extract of  claim 9 , wherein the pH value in step d is between 4.5 and 6.8. 
     
     
         14 . The yeast extract of  claim 9 , wherein the reaction time in step d is between 16 and 20 hrs.